An order fulfillment system for use in supply chains, for example in retail supply chains, may fulfill orders for individual product items, also referred to herein as “eaches,” which are typically packaged and shipped by the manufacturer in containers known as “cases.” The “each” as used herein for convenience purposes, may be considered the most granular unit of handling in retail supply chains.
Traditional order fulfillment facilities store eaches in containers in a multi-level storage structure with a vertical and horizontal array of storage spaces. The storage structure further includes guide rails allowing mobile robots to move horizontally and vertically within the storage structure to transfer containers to and from storage spaces within the structure. It would be advantageous to configure the storage structure and/or mobile robots for quick and efficient locomotion in both the horizontal and vertical directions within the storage structure.